1. Field of the Invention
The present invention relates to an axial piston machine having a plurality of pistons.
2. Description of Related Art
Axial piston machines are hydrostatic pumps or motors that are based on the positive displacement principle. Known axial piston machines have a plurality of pistons kinematically guided in cylindrical bores in a rotating cylinder block, as well as on a pivotable pivoting cradle (swash plate). The pistons are acted upon, at the fluid end of the axial piston machine, by the fluid pressure, the forces created thereby being supported at the opposite piston end on the pivoting cradle, in particular, via in each case at least one sliding block. The force component acting in the direction of the normal to the sliding surface of the pivoting cradle is supported via at least one pivoting bearing, either directly in the housing or indirectly at the housing via a separate bearing shell. Known axial piston machines have suitable actuators for steplessly pivoting the pivoting cradle in the angle it makes with the rotational axis of the cylinder member. The kinematic piston stroke is set via the angle of inclination of the pivoting cradle.
One advantage of known axial piston machines is based on the rapid setting and changing of the fluid flow rate at constant rotational speed. The pivoting bearings used for supporting the pivoting cradle in the housing are frequently developed as hydrostatically supported sliding bearings, which means that the bearing gap has a fluid under pressure applied to it, whereby the pivoting cradle is lifted off from the housing, or rather from the bearing shell, which, in turn, makes possible a rapid, low-resistance pivoting angle adjustment. The fluid exiting from the pivoting cradle bearing is resupplied to a fluid tank, as so-called leakage fluid. In the constructive design of known axial piston machines, care is taken, on the one hand, that the lubricating film (fluid) is sufficiently thick inside the bearing gap, so as to separate the pivoting cradle from the bearing shell and the housing. On the other hand, the leakage flow should turn out to be as low as possible, and the pressure setting pulsation should be kept as low as possible, which is crucial for designing the machine for low noise development. The demands for a sufficiently thick lubricating film and a low leakage flow as well as low pressure setting pulsation are diametrically opposed.